Largeβ-Delayed One and Two Neutron Emission Rates in the Decay ofGa86

Beta decay of ${}^{86}\mathrm{Ga}$ was studied by means of $\beta$-neutron-$\gamma$ spectroscopy. An isotopically pure ${}^{86}\mathrm{Ga}$ beam was produced at the Holifield Radioactive Ion Beam Facility using a resonance ionization laser ion source and high-resolution electromagnetic separation. The decay of ${}^{86}\mathrm{Ga}$ revealed a half-life of ${43}_{-15}^{+21}\mathrm{ms}$ and large $\beta$-delayed one-neutron and two-neutron branching ratios of $P_{1n}=60(10)\%$ and $P_{2n}=20(10)\%$. The $\beta \gamma$ decay of ${}^{86}\mathrm{Ga}$ populated a 527 keV transition that is interpreted as the deexcitation of the first $2^{+}$ state in the $N=54$ isotone ${}^{86}\mathrm{Ge}$ and suggests a quick onset of deformation in Ge isotopes beyond $N=50$.